CA2328696C - Periodic arrayed waveguide grating multiplexer/demultiplexer - Google Patents
Periodic arrayed waveguide grating multiplexer/demultiplexer Download PDFInfo
- Publication number
- CA2328696C CA2328696C CA002328696A CA2328696A CA2328696C CA 2328696 C CA2328696 C CA 2328696C CA 002328696 A CA002328696 A CA 002328696A CA 2328696 A CA2328696 A CA 2328696A CA 2328696 C CA2328696 C CA 2328696C
- Authority
- CA
- Canada
- Prior art keywords
- sub
- band
- channels
- optical
- demultiplexing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Classifications
-
- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B6/00—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings
- G02B6/10—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type
- G02B6/12—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind
- G02B6/12007—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer
- G02B6/12009—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides
- G02B6/12033—Light guides; Structural details of arrangements comprising light guides and other optical elements, e.g. couplings of the optical waveguide type of the integrated circuit kind forming wavelength selective elements, e.g. multiplexer, demultiplexer comprising arrayed waveguide grating [AWG] devices, i.e. with a phased array of waveguides characterised by means for configuring the device, e.g. moveable element for wavelength tuning
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J14/00—Optical multiplex systems
- H04J14/02—Wavelength-division multiplex systems
Abstract
The invention disclosed relates to a device for multiplexing / demultiplexing a multi-band DWDM system, providing reduced insertion losses. The device comprises first and second planar waveguides, a light dispersive element having a periodic frequency spectrum, interconnecting the first and second planar waveguides, a plurality of N input waveguides, connected to the first planar waveguide, and a plurality of M output waveguides, connected to the second planar waveguide, wherein the M outputs are each separated by a frequency interval Af, the N inputs are each separated by M*Af, the free spectral range (FSR) = N*M*.DELTA.f, N is an integer greater than 1, and M is an integer equal to or greater than N. In one embodiment of the invention, wherein the telecommunications window is divided into a plurality of sub-bands of M channels, a temperature controller is included to provide individual temperature set points for each sub-band, to reduce wavelength centering errors.
Description
Doc. No. 10-424 CA Patent Periodic Arrayed Waveguide Grating Multiplexer / Demultiplexer Field of the Invention The present invention relates to periodic arrayed waveguide grating multiplexer /
demultiplexers, particularly multiplexer / demultiplexers for separating periodic sub-bands of multiple channels.
Background of the Invention Optical telecommunications systems currently utilize dense wavelength division multiplexing (DWDM) to transmit multiple optical signals at different wavelengths in order to increase the available bandwidth of the optical fibre network. In the past few years, the number of channels of DWDM systems has dramatically increased from a few channels to more than one hundred channels.
A maximum capacity system is not always required. Service providers would prefer to provide a lower cost system that can be expanded, as demands require. To increase flexibility in the optical telecommunications network, service providers propose dividing the communications window into multiple channel sub-bands, which can be addressed modularly as system hardware upgrades are required.
To support a modular sub-band system, a multiplexer / demultiplexer adapted for use with sub-bands of multiple channels smaller than the whole DWDM system is required.
For practical reasons, this discussion refers to 40 channels of the optical telecommunications window at the standardized 100 GHz ITU channel spacing. It is understood, however, that this is just an application example and that a larger or smaller number of channels and different channel spacing can just as easily be accommodated.
Doc. No. 10-424 CA Patent An arrayed waveguide grating (AWG) is a dispersive optical device suitable for multiplexing and demultiplexing a large number of channels simultaneously.
Channel signals on each channel of a 40 channel system can be multiplexed and demultiplexed in a single AWG.
Selecting an appropt-iate multiplexer / demultiplexer for a modular system of multi-channel sub-bands introduces difficulties for the service provider in hat-dware costs and complexity. If only a small subset of all the channels must be multiplexed /
demultiplexed, then unnecessary losses and complexity are introduced by using a large device to multiplex / demultiplex the whole set. If a large capacity AWG is used instead, to only pick up any selected smaller subset of channels, then a large switching router is needed to couple the selected outputs. Altet-natively, an AWG can be designed and optimized for any specific subset of channels. However, for the service provider to provide service at a selected sub-band of channels and later add service for additional sub-bands, it is costly and inconvenient to maintain a specific AWG foi- each multi-channel sub-band.
Thus, it is desired to provide a single multiplexer / demultiplexer that can multiplex /
demultiplex any selected multiple channel sub-band of a plurality of sub-bands. Since the AWG is a periodic device in frequency, it can be used to address more than one sub-band, given that the sub-bands are equal to the free spectral range (FSR) of the AWG.
However, this is not sufficient to design a suitable multiplexer /
demultiplexer, because unacceptable losses are experienced in such a device. A better multiplexer /
demultiplexer is still needed to provide a modular system of multiple channel sub-bands.
A prior art device is described in a paper, Transmission Characteristics of Arrayed Waveguide N x N Wavelength Multiplexer by H. Takahashi et al., Jout-nal of Lightwave Technology, Vol. 13, No. 3, March 1995. In the device described, a router is constructed having a same number (N) of input and output waveguides. The N x N routing is achieved by using the periodicity of an AWG. By selecting different inputs, an order of output channels can be shifted. Each output has periodic pass frequencies for routing any
demultiplexers, particularly multiplexer / demultiplexers for separating periodic sub-bands of multiple channels.
Background of the Invention Optical telecommunications systems currently utilize dense wavelength division multiplexing (DWDM) to transmit multiple optical signals at different wavelengths in order to increase the available bandwidth of the optical fibre network. In the past few years, the number of channels of DWDM systems has dramatically increased from a few channels to more than one hundred channels.
A maximum capacity system is not always required. Service providers would prefer to provide a lower cost system that can be expanded, as demands require. To increase flexibility in the optical telecommunications network, service providers propose dividing the communications window into multiple channel sub-bands, which can be addressed modularly as system hardware upgrades are required.
To support a modular sub-band system, a multiplexer / demultiplexer adapted for use with sub-bands of multiple channels smaller than the whole DWDM system is required.
For practical reasons, this discussion refers to 40 channels of the optical telecommunications window at the standardized 100 GHz ITU channel spacing. It is understood, however, that this is just an application example and that a larger or smaller number of channels and different channel spacing can just as easily be accommodated.
Doc. No. 10-424 CA Patent An arrayed waveguide grating (AWG) is a dispersive optical device suitable for multiplexing and demultiplexing a large number of channels simultaneously.
Channel signals on each channel of a 40 channel system can be multiplexed and demultiplexed in a single AWG.
Selecting an appropt-iate multiplexer / demultiplexer for a modular system of multi-channel sub-bands introduces difficulties for the service provider in hat-dware costs and complexity. If only a small subset of all the channels must be multiplexed /
demultiplexed, then unnecessary losses and complexity are introduced by using a large device to multiplex / demultiplex the whole set. If a large capacity AWG is used instead, to only pick up any selected smaller subset of channels, then a large switching router is needed to couple the selected outputs. Altet-natively, an AWG can be designed and optimized for any specific subset of channels. However, for the service provider to provide service at a selected sub-band of channels and later add service for additional sub-bands, it is costly and inconvenient to maintain a specific AWG foi- each multi-channel sub-band.
Thus, it is desired to provide a single multiplexer / demultiplexer that can multiplex /
demultiplex any selected multiple channel sub-band of a plurality of sub-bands. Since the AWG is a periodic device in frequency, it can be used to address more than one sub-band, given that the sub-bands are equal to the free spectral range (FSR) of the AWG.
However, this is not sufficient to design a suitable multiplexer /
demultiplexer, because unacceptable losses are experienced in such a device. A better multiplexer /
demultiplexer is still needed to provide a modular system of multiple channel sub-bands.
A prior art device is described in a paper, Transmission Characteristics of Arrayed Waveguide N x N Wavelength Multiplexer by H. Takahashi et al., Jout-nal of Lightwave Technology, Vol. 13, No. 3, March 1995. In the device described, a router is constructed having a same number (N) of input and output waveguides. The N x N routing is achieved by using the periodicity of an AWG. By selecting different inputs, an order of output channels can be shifted. Each output has periodic pass frequencies for routing any
2 Doc. No. 10-424 CA Patent one channel of a multiplexed signal to any output. In this device, the N x N
connection is provided when FSR = N*AF, wherein Af is the frequency channel spacing set at GHz. An insertion loss of 3dB is claimed.
Summary of the Invention The present invention has found that by designing a periodic dispersive element, particularly an arrayed waveguide grating with an FSR broader than the selected sub-band width by a multiple corresponding to a number of inputs greater than one, any selected multiple channel sub-band in the range of wavelengths of interest can be multiplexed or demultiplexed. And further, that by optimizing the number of inputs and outputs, losses can be significantly reduced.
Accordingly, the present invention provides an optical multiplexer /
demultiplexer for multiplexing / demultiplexing any selected sub-band of M adjacent channels of optical frequencies from a plurality of sub-bands comprising:
a first planar waveguide;
a second planar waveguide;
an arrayed waveguide grating optically coupling the first and second planar waveguides having a periodic free spectral range;
a plurality of spaced apart inputs N coupled to the first planar waveguide, the N inputs for launching complementary sub-band frequencies of adjacent channels in a demultiplexing mode of operation, or for outputting a multiplexed band of adjacent channels in a multiplexing mode of operation;
a plurality of spaced apart outputs M coupled to the second planar waveguide for receiving demultiplexed output channel frequencies of an input sub-band in a demultiplexing mode of operation, oi- for launching a plurality of adjacent channel frequencies in a multiplexing mode of operation;
connection is provided when FSR = N*AF, wherein Af is the frequency channel spacing set at GHz. An insertion loss of 3dB is claimed.
Summary of the Invention The present invention has found that by designing a periodic dispersive element, particularly an arrayed waveguide grating with an FSR broader than the selected sub-band width by a multiple corresponding to a number of inputs greater than one, any selected multiple channel sub-band in the range of wavelengths of interest can be multiplexed or demultiplexed. And further, that by optimizing the number of inputs and outputs, losses can be significantly reduced.
Accordingly, the present invention provides an optical multiplexer /
demultiplexer for multiplexing / demultiplexing any selected sub-band of M adjacent channels of optical frequencies from a plurality of sub-bands comprising:
a first planar waveguide;
a second planar waveguide;
an arrayed waveguide grating optically coupling the first and second planar waveguides having a periodic free spectral range;
a plurality of spaced apart inputs N coupled to the first planar waveguide, the N inputs for launching complementary sub-band frequencies of adjacent channels in a demultiplexing mode of operation, or for outputting a multiplexed band of adjacent channels in a multiplexing mode of operation;
a plurality of spaced apart outputs M coupled to the second planar waveguide for receiving demultiplexed output channel frequencies of an input sub-band in a demultiplexing mode of operation, oi- for launching a plurality of adjacent channel frequencies in a multiplexing mode of operation;
3 Doc. No. 10-424 CA Patent wherein the M outputs are separated to provide a spectral frequency interval Af, the inputs are separated to provide complementary input sub-band frequencies each spectrally separated by M*Af, and the free spectral range of the device equals N*M*Af.
Advantageously, the arrayed waveguide grating in accordance with the present invention can provide multiplexing / demultiplexing functionality for any channel sub-band over a broad channel spectrum.
Further advantages of the present invention will be apparent to those of skill in the art from the following figures, which illustrate preferred examples of the invention by example only.
Brief Description of Figures Figure 1 graphically illustrates a multi-band DWDM system divided into sub-bands;
Figure 2 illustrates an arrayed waveguide grating having multiple inputs and multiple outputs in accordance with the present invention;
Figure 3 graphically illustrates a first spectral output from the AWG of Fig.
2;
Figure 4 graphically illustrates a second complementary spectral output from the AWG of Fig. 2;
Figure 5 graphically illustrates a wavelength centering error experienced by the AWG of Fig. 2; and Figure 6 graphically illustrates the wavelength centering error of Fig. 5 modified by temperature compensation.
Detailed Description of Preferred Embodiments Figure 1 shows a 40 channel telecommunications window divided into 10 sub-bands SB1...SB10 of four channels each, the channels being separated by the standardized 100 GHz spacing. This division into sub-bands of four channels is arbitrary, and any number of adjacent channels can be selected in accordance with the present invention.
Advantageously, the arrayed waveguide grating in accordance with the present invention can provide multiplexing / demultiplexing functionality for any channel sub-band over a broad channel spectrum.
Further advantages of the present invention will be apparent to those of skill in the art from the following figures, which illustrate preferred examples of the invention by example only.
Brief Description of Figures Figure 1 graphically illustrates a multi-band DWDM system divided into sub-bands;
Figure 2 illustrates an arrayed waveguide grating having multiple inputs and multiple outputs in accordance with the present invention;
Figure 3 graphically illustrates a first spectral output from the AWG of Fig.
2;
Figure 4 graphically illustrates a second complementary spectral output from the AWG of Fig. 2;
Figure 5 graphically illustrates a wavelength centering error experienced by the AWG of Fig. 2; and Figure 6 graphically illustrates the wavelength centering error of Fig. 5 modified by temperature compensation.
Detailed Description of Preferred Embodiments Figure 1 shows a 40 channel telecommunications window divided into 10 sub-bands SB1...SB10 of four channels each, the channels being separated by the standardized 100 GHz spacing. This division into sub-bands of four channels is arbitrary, and any number of adjacent channels can be selected in accordance with the present invention.
4 Doc. No. 10-424 CA Patent Figure 2 shows an illustrative embodiment of a multiplexer / demultiplexer device 10 according to the invention, including an arrayed waveguide grating 12 comprising a plurality of unequal length waveguides, a plurality of input waveguides 14, a plurality of output waveguides 16, and first and second planar waveguides 18 and 20, respectively.
The entire device may be integrated on the same substrate chip using known techniques.
The first and second planar waveguides 18 and 20 are interconnected by an AWG
12 in which the lengths of adjacent waveguides 22 differ by a constant value and increase geometrically from one side to the other, as provided for in the design. This structure produces an output response that is periodic in frequency.
The periodic response can be described as the free spectral i-ange (FSR) of the device.
The FSR is shown as a frequency period in Fig. 3 as 800 GHz. In order to design a multiplexer / demultiplexer suitable for all sub-bands in a wavelength range of interest, the FSR should, one would assume, be limited to frequency range to incorporate one sub-band of channels, for example for a four channel system an FSR=400 GHz. Then with only one input 14, the periodicity (FSR) will cause each channel of a sub-band to be demultiplexed to an output 16 of the device 10, at different orders of the grating for evet-y sub-band. However, high losses in the range of 3 dB attributed as roll-off would be experienced in such a system. The FSR defines a maximum power envelope that has a normally Gaussian shape between zero loss and -3 dB. The Gaussian envelope is illustrated as 30 in Fig. 4, as designed for an example of the present invention. The smaller the FSR, the smaller the envelope, and consequently fewer channels can be passed in the low loss portion of the envelope.
The present invention has found that the FSR can be broadened to permit more channels to pass within the low loss portion of the envelope, to reduce roll-off losses, if the number of inputs is increased. An output response, as illustrated in Figs. 3 and 4, results having complementary output sub-bands from each input passed under a broader 800 GHz envelope, as shown in Fig. 4. When the number of inputs is greater than one, input roll-off must also be factored into optimizing calculations. In the example shown in Figs. 2-4, channel bands of four channels are selected, thus the device 10 has 4 outputs 16. By
The entire device may be integrated on the same substrate chip using known techniques.
The first and second planar waveguides 18 and 20 are interconnected by an AWG
12 in which the lengths of adjacent waveguides 22 differ by a constant value and increase geometrically from one side to the other, as provided for in the design. This structure produces an output response that is periodic in frequency.
The periodic response can be described as the free spectral i-ange (FSR) of the device.
The FSR is shown as a frequency period in Fig. 3 as 800 GHz. In order to design a multiplexer / demultiplexer suitable for all sub-bands in a wavelength range of interest, the FSR should, one would assume, be limited to frequency range to incorporate one sub-band of channels, for example for a four channel system an FSR=400 GHz. Then with only one input 14, the periodicity (FSR) will cause each channel of a sub-band to be demultiplexed to an output 16 of the device 10, at different orders of the grating for evet-y sub-band. However, high losses in the range of 3 dB attributed as roll-off would be experienced in such a system. The FSR defines a maximum power envelope that has a normally Gaussian shape between zero loss and -3 dB. The Gaussian envelope is illustrated as 30 in Fig. 4, as designed for an example of the present invention. The smaller the FSR, the smaller the envelope, and consequently fewer channels can be passed in the low loss portion of the envelope.
The present invention has found that the FSR can be broadened to permit more channels to pass within the low loss portion of the envelope, to reduce roll-off losses, if the number of inputs is increased. An output response, as illustrated in Figs. 3 and 4, results having complementary output sub-bands from each input passed under a broader 800 GHz envelope, as shown in Fig. 4. When the number of inputs is greater than one, input roll-off must also be factored into optimizing calculations. In the example shown in Figs. 2-4, channel bands of four channels are selected, thus the device 10 has 4 outputs 16. By
5 Doc. No. 10-424 CA Patent optimizing input and output roll-off an optimum number of 2 inputs 14 is selected.
Calculations shown in Table 1 of expected roll-off losses for a 4 channel sub-band illustrate how this selection is made.
N M Input roll-off Output roll-off Total losses 1 4 0 1.63 1.63 8 0 2.15 2.15 16 0 2.45 2.45 2 4 .75 0.4 1.15 8 .75 0.6 1.35 16 .75 0.7 1.45 4 4 1.63 0.2 1.83 8 1.63 0.23 1.86 16 1.63 0.28 1.91 Table 1 As can be seen in the table, the AWG of the present example having 2 inputs and 4 outputs has a calculated colnbined loss of only 1.15 dB, rather than the 1.63 dB losses of a single input of a 400 GHz FSR grating.
To obtain a multiplexer / demultiplexer designed for all channels, the FSR
must be equal to the number of inputs N times the number of outputs M times the channel spacing Af, where N and M ai-e greater than 1. Thus, FSR=N*M*Af. The N input sub-band frequencies must have a spectral separation of M*Af and the M output channel frequencies must have a spectral separation of Af. In the illustrated example, N=2, M=4 and Af=IOOGHz, so the FSR= 800GHz. To achieve a spectral separation of M*Af at the inputs N the design must provide a selected physical separation between the inputs 14 known from the dispersion relation between physical sepai-ation in a dispet-sive element and specti-al separation.
In order to configure the device 10 for a selected channel band, the correct input 14 must be selected. This can be done statically connecting the selected input permanently upon installation, or dynamically with a simple 1xN switch (not shown) in this case 1x2.
Calculations shown in Table 1 of expected roll-off losses for a 4 channel sub-band illustrate how this selection is made.
N M Input roll-off Output roll-off Total losses 1 4 0 1.63 1.63 8 0 2.15 2.15 16 0 2.45 2.45 2 4 .75 0.4 1.15 8 .75 0.6 1.35 16 .75 0.7 1.45 4 4 1.63 0.2 1.83 8 1.63 0.23 1.86 16 1.63 0.28 1.91 Table 1 As can be seen in the table, the AWG of the present example having 2 inputs and 4 outputs has a calculated colnbined loss of only 1.15 dB, rather than the 1.63 dB losses of a single input of a 400 GHz FSR grating.
To obtain a multiplexer / demultiplexer designed for all channels, the FSR
must be equal to the number of inputs N times the number of outputs M times the channel spacing Af, where N and M ai-e greater than 1. Thus, FSR=N*M*Af. The N input sub-band frequencies must have a spectral separation of M*Af and the M output channel frequencies must have a spectral separation of Af. In the illustrated example, N=2, M=4 and Af=IOOGHz, so the FSR= 800GHz. To achieve a spectral separation of M*Af at the inputs N the design must provide a selected physical separation between the inputs 14 known from the dispersion relation between physical sepai-ation in a dispet-sive element and specti-al separation.
In order to configure the device 10 for a selected channel band, the correct input 14 must be selected. This can be done statically connecting the selected input permanently upon installation, or dynamically with a simple 1xN switch (not shown) in this case 1x2.
6 Doc. No. 10-424 CA Patent There is a further en-or that must be compensated fot- in order to use a same AWG device effectively over the full range of channel bands. As is known in the art, there are only discrete values possible fot- an FSR of an arl-ayed waveguide grating. Accoi-dingly, the best FSR selected may not provide channel passbands exactly centered on the ITU grid.
As a result, there is an increasing wavelength centering error of the channels that correspond to lower orders of the grating. The problem is graphically illustrated in Fig.
5. Fig. 5 shows the wavelength centering error for a 56 channel system whet-e N=2 and M=4. Each of the linked channel sub-bands is distributed progressively farther ft-om zero displacement about the center wavelength bands. A further unavoidable dispersion error, shown in Fig. 5 as the diffei-ent slopes of the sub-bands, t-esults from using different grating orders which have different wavelength dispersions.
From Fig. 6 it can be seen that by providing a different tempei-atui-e set point for each sub-band, the sub-bands ai-e all brought to a centered position. The individual set points are obtained by heating the chip selectively for each sub-band using a tempei-ature controller (not shown). In the present example, a worst wavelength centering ei-ror is improved from 68 pm to18 pm when the AWG tempet-atut-e set point is adjusted for each sub-band. Other known techniques can also be used to correct the wavelength centering error, such as moving the input position or sti-essing the device.
It will be appreciated by those skilled in the art that while the invention has been desci-ibed and illustrated by an AWG, other dispersive elements having a periodic frequency spectrum could also be employed. Bulk optical devices such as diffraction gratings and holographic gratings can be used.
As a result, there is an increasing wavelength centering error of the channels that correspond to lower orders of the grating. The problem is graphically illustrated in Fig.
5. Fig. 5 shows the wavelength centering error for a 56 channel system whet-e N=2 and M=4. Each of the linked channel sub-bands is distributed progressively farther ft-om zero displacement about the center wavelength bands. A further unavoidable dispersion error, shown in Fig. 5 as the diffei-ent slopes of the sub-bands, t-esults from using different grating orders which have different wavelength dispersions.
From Fig. 6 it can be seen that by providing a different tempei-atui-e set point for each sub-band, the sub-bands ai-e all brought to a centered position. The individual set points are obtained by heating the chip selectively for each sub-band using a tempei-ature controller (not shown). In the present example, a worst wavelength centering ei-ror is improved from 68 pm to18 pm when the AWG tempet-atut-e set point is adjusted for each sub-band. Other known techniques can also be used to correct the wavelength centering error, such as moving the input position or sti-essing the device.
It will be appreciated by those skilled in the art that while the invention has been desci-ibed and illustrated by an AWG, other dispersive elements having a periodic frequency spectrum could also be employed. Bulk optical devices such as diffraction gratings and holographic gratings can be used.
7
Claims (12)
1. An optical multiplexer / demultiplexer for multiplexing / demultiplexing any selected sub-band of M adjacent channels of optical frequencies from a plurality of sub-bands comprising:
a first planar waveguide;
a second planar waveguide;
a plurality of spaced apart individually selectable waveguide inputs N coupled to the first planar waveguide, the N inputs being separated to provide complementary input sub-band frequencies each spectrally separated by substantially M*.DELTA.f, the N
inputs for launching complementary sub-band frequencies of adjacent channels in a demultiplexing mode of operation, or for outputting a multiplexed band of adjacent channels in a multiplexing mode of operation;
a plurality of spaced apart waveguide outputs M coupled to the second planar waveguide, the M outputs being separated to provide a spectral frequency interval .DELTA.f, for receiving demultiplexed output channel frequencies of an input sub-band in a demultiplexing mode of operation, or for launching a plurality of adjacent channel frequencies in a multiplexing mode of operation; and an arrayed waveguide grating optically coupling the first and second planar waveguides having a periodic free spectral range equal to substantially N*M*.DELTA.f.
a first planar waveguide;
a second planar waveguide;
a plurality of spaced apart individually selectable waveguide inputs N coupled to the first planar waveguide, the N inputs being separated to provide complementary input sub-band frequencies each spectrally separated by substantially M*.DELTA.f, the N
inputs for launching complementary sub-band frequencies of adjacent channels in a demultiplexing mode of operation, or for outputting a multiplexed band of adjacent channels in a multiplexing mode of operation;
a plurality of spaced apart waveguide outputs M coupled to the second planar waveguide, the M outputs being separated to provide a spectral frequency interval .DELTA.f, for receiving demultiplexed output channel frequencies of an input sub-band in a demultiplexing mode of operation, or for launching a plurality of adjacent channel frequencies in a multiplexing mode of operation; and an arrayed waveguide grating optically coupling the first and second planar waveguides having a periodic free spectral range equal to substantially N*M*.DELTA.f.
2. An optical multiplexer / demultiplexer as defined in claim 1, further including means for selecting an input of the plurality of N inputs for launching a sub-band of M
adjacent channels.
adjacent channels.
3. An optical multiplexer / demultiplexer as defined in claim 2, wherein M>N.
4. An optical multiplexer / demultiplexer as defined in claim 3, wherein N=2 and M=4.
5. An optical multiplexer / demultiplexer as defined in claim 1, further comprising a temperature controller for adjusting the temperature of the arrayed waveguide grating providing an individual temperature set point for each sub-band.
6. An optical multiplexer / demultiplexer for multiplexing / demultiplexing a plurality of sub-bands of optical channel frequencies, each sub-band having M
adjacent channel frequencies comprising:
a periodic dispersive optical element having a free spectral range equal to an integer multiple N, where N is greater than 1, of a frequency width of a sub-band of M channels, said periodic light dispersive optical element optically coupling a plurality of inputs N, equal to the integer multiple, separated to provide selected input sub-band frequencies spectrally separated by M*.DELTA.f, for launching light into the periodic dispersive optical element in a demultiplexing mode of operation, or for outputting a multiplexed band of adjacent channels in a multiplexing mode of operation; and, a plurality of outputs M, separated to provide a spectral frequency interval of .DELTA.f, for receiving M demultiplexed channels of a sub-band from the periodic dispersive optical element in a demultiplexing mode of operation, or for launching a plurality of adjacent channel frequencies in a multiplexing mode of operation.
adjacent channel frequencies comprising:
a periodic dispersive optical element having a free spectral range equal to an integer multiple N, where N is greater than 1, of a frequency width of a sub-band of M channels, said periodic light dispersive optical element optically coupling a plurality of inputs N, equal to the integer multiple, separated to provide selected input sub-band frequencies spectrally separated by M*.DELTA.f, for launching light into the periodic dispersive optical element in a demultiplexing mode of operation, or for outputting a multiplexed band of adjacent channels in a multiplexing mode of operation; and, a plurality of outputs M, separated to provide a spectral frequency interval of .DELTA.f, for receiving M demultiplexed channels of a sub-band from the periodic dispersive optical element in a demultiplexing mode of operation, or for launching a plurality of adjacent channel frequencies in a multiplexing mode of operation.
7. An optical multiplexer / demultiplexer as defined in claim 6, wherein the periodic light dispersive optical element is selected from the group comprising: an arrayed waveguide grating, a diffraction grating, and a holographic grating.
8. An optical multiplexer / demultiplexer as defined in claim 7, wherein M>N.
9. An optical multiplexer / demultiplexer as defined in claim 8, further comprising a temperature controller for adjusting the temperature of the arrayed waveguide grating providing an individual temperature set point for each sub-band.
10. A method of demultiplexing a sub-band of M adjacent optical channels from a plurality of optical channels having a channel spacing of .DELTA.f comprising the steps of:
demultiplexing a sub-band of M multiplexed channels from the plurality of optical channels;
launching the sub-band of M channels into an input of a periodic dispersive optical element having a plurality N of inputs separated to provide a spectral separation of M*.DELTA.f and a plurality M of outputs, separated to receive output spectral frequencies separated by .DELTA.f, and a free spectral range equal to N*M*
.DELTA.f; and distributing M channel frequencies in a periodic order of the dispersive optical element to the M outputs.
demultiplexing a sub-band of M multiplexed channels from the plurality of optical channels;
launching the sub-band of M channels into an input of a periodic dispersive optical element having a plurality N of inputs separated to provide a spectral separation of M*.DELTA.f and a plurality M of outputs, separated to receive output spectral frequencies separated by .DELTA.f, and a free spectral range equal to N*M*
.DELTA.f; and distributing M channel frequencies in a periodic order of the dispersive optical element to the M outputs.
11. A method of demultiplexing a sub-band of M adjacent optical channels as defined in claim 10, further comprising the step of:
demultiplexing an other sub-band of M different multiplexed adjacent optical channels from the plurality of optical channels;
launching the other sub-band of M channels into an other input, of the plurality of inputs N, of the periodic dispersive optical element; and distributing M different channel frequencies in an other periodic order of the dispersive optical element to the M outputs.
demultiplexing an other sub-band of M different multiplexed adjacent optical channels from the plurality of optical channels;
launching the other sub-band of M channels into an other input, of the plurality of inputs N, of the periodic dispersive optical element; and distributing M different channel frequencies in an other periodic order of the dispersive optical element to the M outputs.
12. A method of demultiplexing a sub-band of M adjacent optical channels as defined in claim 11, including the step of switching an optical coupling between the input and the other input before launching an adjacent sub-band of M optical channels.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002328696A CA2328696C (en) | 2000-12-18 | 2000-12-18 | Periodic arrayed waveguide grating multiplexer/demultiplexer |
| US10/014,354 US6608948B2 (en) | 2000-12-18 | 2001-12-14 | Periodic arrayed waveguide grating multiplexer/demultiplexer |
| CNB011433035A CN1224853C (en) | 2000-12-18 | 2001-12-18 | Cyclic array waveguide raster multiplexer/demultiplexer |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA002328696A CA2328696C (en) | 2000-12-18 | 2000-12-18 | Periodic arrayed waveguide grating multiplexer/demultiplexer |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2328696A1 CA2328696A1 (en) | 2002-06-18 |
| CA2328696C true CA2328696C (en) | 2008-08-12 |
Family
ID=4167937
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002328696A Expired - Fee Related CA2328696C (en) | 2000-12-18 | 2000-12-18 | Periodic arrayed waveguide grating multiplexer/demultiplexer |
Country Status (3)
| Country | Link |
|---|---|
| US (1) | US6608948B2 (en) |
| CN (1) | CN1224853C (en) |
| CA (1) | CA2328696C (en) |
Families Citing this family (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7006719B2 (en) * | 2002-03-08 | 2006-02-28 | Infinera Corporation | In-wafer testing of integrated optical components in photonic integrated circuits (PICs) |
| US20050186416A1 (en) * | 2004-02-25 | 2005-08-25 | 3M Innnovative Properties Company | Hydrophilic articles |
| US7423804B2 (en) * | 2004-10-06 | 2008-09-09 | Jds Uniphase Corporation | Spectrally resolved fast monitor |
| US8160411B2 (en) * | 2006-12-28 | 2012-04-17 | Nokia Corporation | Device for expanding an exit pupil in two dimensions |
| US8111996B2 (en) * | 2008-02-22 | 2012-02-07 | Infinera Corporation | Compact optical multiplexer and demultiplexer |
| US8204346B2 (en) * | 2009-11-21 | 2012-06-19 | Corrado Pietro Dragone | Optical router with nearly ideal performance |
| EP2628037B1 (en) | 2010-10-12 | 2018-05-23 | Gemfire Corporation | Awg supporting multiple frequency bands and channel plans |
| KR101747453B1 (en) * | 2012-02-29 | 2017-06-16 | 한국전자통신연구원 | Array waveguide grating router integrated wave multiplexing and wave demultiplexing |
| JP6126522B2 (en) * | 2013-12-09 | 2017-05-10 | 日本電信電話株式会社 | Optical wavelength multiplexing / demultiplexing circuit |
| CN106199829A (en) * | 2016-08-25 | 2016-12-07 | 武汉光迅科技股份有限公司 | A kind of array waveguide grating with channel monitoring function |
| JP7075747B2 (en) * | 2017-12-06 | 2022-05-26 | Ｎｔｔエレクトロニクス株式会社 | Optical wavelength combiner / demultiplexer |
| TWI719870B (en) * | 2020-03-31 | 2021-02-21 | 國立高雄科技大學 | Wave division multiplexing device for large-capacity optical transmission |
Family Cites Families (25)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5002350A (en) | 1990-02-26 | 1991-03-26 | At&T Bell Laboratories | Optical multiplexer/demultiplexer |
| US5136671A (en) | 1991-08-21 | 1992-08-04 | At&T Bell Laboratories | Optical switch, multiplexer, and demultiplexer |
| DE59503996D1 (en) * | 1994-06-28 | 1998-11-26 | Siemens Ag | DEVICE FOR SPACIOUS SEPARATION AND / OR COMBINATION OF OPTICAL WAVELENGTH CHANNELS |
| US5745612A (en) * | 1995-12-18 | 1998-04-28 | International Business Machines Corporation | Wavelength sorter and its application to planarized dynamic wavelength routing |
| GB2316759A (en) * | 1996-07-30 | 1998-03-04 | Northern Telecom Ltd | Optical multiplexer/demultiplexer having diffraction gratings in tandem |
| US5809184A (en) * | 1996-10-15 | 1998-09-15 | Doerr; Christopher Richard | Polarization diversity waveguide grating receiver |
| US6137939A (en) * | 1997-10-01 | 2000-10-24 | Lucent Technologies Inc. | Method and apparatus for reducing temperature-related spectrum shifts in optical devices |
| US6111996A (en) * | 1998-03-13 | 2000-08-29 | Northern Telecom Limited | Optical multiplexer/demultiplexer |
| GB2334343A (en) * | 1998-02-13 | 1999-08-18 | Northern Telecom Ltd | Optical waveguide multiplexer/demultiplexer with diffraction gratings embracing one another |
| KR100274804B1 (en) * | 1998-04-22 | 2001-01-15 | 윤종용 | Bi-directional optical wavelength multiplexer and demultiplexer |
| JP2000131540A (en) * | 1998-10-22 | 2000-05-12 | Furukawa Electric Co Ltd:The | Optical multiplexing/demultiplexing device |
| JP3615069B2 (en) * | 1998-12-09 | 2005-01-26 | 古河電気工業株式会社 | Arrayed waveguide grating optical multiplexer / demultiplexer |
| KR100322133B1 (en) * | 1999-02-01 | 2002-02-04 | 윤종용 | Optical multiplexer/demultiplexer having uniform loss |
| US6445847B1 (en) * | 1999-02-24 | 2002-09-03 | Lucent Technologies Inc. | Apparatus and method for achieving a smooth spectral response optical filter |
| US6205273B1 (en) * | 1999-03-02 | 2001-03-20 | Lucent Technologies Inc. | Waveguide grating router having a predetermined composite amplitude spectrum |
| JP3403353B2 (en) * | 1999-04-05 | 2003-05-06 | 古河電気工業株式会社 | WDM communication module |
| US6421478B1 (en) * | 1999-05-11 | 2002-07-16 | Jds Fitel Inc. | Tapered MMI coupler |
| US6263127B1 (en) * | 1999-05-13 | 2001-07-17 | Lucent Technologies Inc. | Free-space/arrayed-waveguide router |
| US6442311B1 (en) * | 1999-07-09 | 2002-08-27 | Agere Systems Guardian Corp. | Optical device having modified transmission characteristics by localized thermal treatment |
| JP2001083341A (en) * | 1999-09-13 | 2001-03-30 | Furukawa Electric Co Ltd:The | Array waveguide type diffraction grating |
| US6236781B1 (en) * | 1999-09-30 | 2001-05-22 | Agere Systems Optoelectronics Guardian Corp. | Duplicated-port waveguide grating router having substantially flat passbands |
| US6374013B1 (en) * | 1999-12-23 | 2002-04-16 | Nortel Networks Limited | Optical arrayed waveguide grating devices |
| US6301409B1 (en) * | 1999-12-23 | 2001-10-09 | Nortel Networks Limited | Optical comb filter |
| US6266464B1 (en) * | 1999-12-23 | 2001-07-24 | Nortel Networks Limited | Optical arrayed waveguide grating devices |
| US6298186B1 (en) * | 2000-07-07 | 2001-10-02 | Metrophotonics Inc. | Planar waveguide grating device and method having a passband with a flat-top and sharp-transitions |
-
2000
- 2000-12-18 CA CA002328696A patent/CA2328696C/en not_active Expired - Fee Related
-
2001
- 2001-12-14 US US10/014,354 patent/US6608948B2/en not_active Expired - Lifetime
- 2001-12-18 CN CNB011433035A patent/CN1224853C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1360415A (en) | 2002-07-24 |
| CN1224853C (en) | 2005-10-26 |
| US6608948B2 (en) | 2003-08-19 |
| CA2328696A1 (en) | 2002-06-18 |
| US20020114560A1 (en) | 2002-08-22 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US6868201B1 (en) | Reconfigurable WDM mux/demux/OADM | |
| EP0985289B1 (en) | Optical multiplexing and demultiplexing | |
| US7088922B2 (en) | Wavelength division multiplexing optical communication system | |
| US20040252996A1 (en) | Flexible banded MUX/DEMUX architecture for WDM systems | |
| US8095011B2 (en) | Wavelength division multiplexing filter, wavelength division multiplexing system, and wavelength division multiplexing method | |
| US20050129404A1 (en) | Apparatus for providing broadcasting service through overlay structure in WDM-PON | |
| CA2275062A1 (en) | Add/drop filter for a multi-wavelength lightwave system | |
| WO2003065621A1 (en) | A method for decreasing and compensating the transmission loss at a wavelength-division-multiplexed passive optical network and an apparatus therefor | |
| EP1225461B1 (en) | Bidirectional multiplexer and demultiplexer based on a single echelle waveguide grating | |
| CA2328696C (en) | Periodic arrayed waveguide grating multiplexer/demultiplexer | |
| US7945165B2 (en) | Optical signal synchronizer | |
| EP1638232A2 (en) | Optical demultiplexing method and optical multiplexing method, and optical transmission apparatus using same | |
| US8073333B2 (en) | Multiplex delay unit | |
| JP4278628B2 (en) | Optical transmission system | |
| US6690853B1 (en) | Tunable DWDM demultiplexer | |
| US6963684B2 (en) | Multi-band arrayed waveguide grating with improved insertion loss and wavelength accuracy | |
| US6650809B2 (en) | Multiple band optical multiplexer and demultiplexer | |
| US20030206743A1 (en) | Cross connecting device and optical communication system | |
| EP1009120A2 (en) | Multichannel optical ADD/DROP, multiplexor/demultiplexor | |
| US6912340B2 (en) | Optical ring interconnect | |
| WO1999008143A1 (en) | Optical wavelength division multiplexer | |
| JP2004241855A (en) | Optical network system | |
| US6901184B2 (en) | Frequency comb for an optical WDM network | |
| CA2344541C (en) | Optical multiplexer, demultiplexer and methods | |
| JP2000206362A (en) | OPTICAL ADM(Add/Drop Multiplexing) NODE DEVICE |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |
Effective date: 20131218 |